The invention concerns a method for operating a gear pump, a gear pump and a vehicle, in particular a truck, and/or an internal combustion engine for performance of the method and/or with the gear pump.
It is known to deliver oil, in particular engine oil, in an oil circuit of a motor vehicle using a gear pump. The gear pump may for example be configured as an internal gear pump in which at least one externally toothed gear wheel intermeshes with at least one internally toothed gear wheel. Such an internal gear pump is normally driven via the internally toothed gear wheel. Furthermore it is also known to configure a gear pump as an external gear pump in which at least one externally toothed gear wheel intermeshes with at least one further externally toothed gear wheel. The external gear pump is here driven by at least one of these externally toothed gear wheels. The oil or fluid to be conveyed is delivered by the tooth gaps between the individual teeth of the gear wheels. These gaps form delivery chambers which deliver the fluid to be conveyed in the rotation direction of the respective gear wheel.
Furthermore, it is also known in an external gear pump to split the teeth axially or arrange at least two gear wheels behind each other viewed in the axial direction. The split teeth are then usually arranged rotated relative to each other by half a tooth pitch. In this way the amplitudes of the pressure pulses occurring on operation of the gear pump can be reduced, since the volume of the delivery chambers is diminished and the viscosity of the fluid has a damping effect when the fluid flows from one delivery chamber to the next delivery chamber. Too great an amplitude of the pressure pulses in an oil circuit can for example frequently lead to an overload of oil coolers, overpressure valves and further elements of the oil circuit.
DE 197 46 768 A1 for example discloses a gear mechanism with a drive train comprising at least two gear trains, the gear wheels of which are guided with their hubs on at least two shafts mounted rotatably in the housing. The driven gear wheels of the at least two gear pairs are arranged together on one of the shafts and coupled rotationally fixedly to this one shaft via an external toothing formed on this one shaft and an internal toothing formed in the hubs of the driven gear wheels. The external toothing of the shaft here consists of at least two toothing parts spaced apart from each other and having a tooth-offset to each other, and each assigned to one of the driven gear wheels. In this way it is simply and reliably ensured that the gear wheels are fixed to the common shaft, offset to each other by half a tooth pitch, on installation.
The twist of the split gear wheels relative to each other however has a negative effect on the suction capacity of the gear pump, and hence also on the flow rate of the gear pump, in particular because of the flow of the fluid to be conveyed from one delivery chamber to the adjacent delivery chamber. This is a problem for example in defined operating situations of the gear pump when a gear pump is used in an oil circuit of a vehicle.